Various kinds of fat aspiration and fat transplantation have been already performed, but fat transplantation has a problem that its application range is little due to many limitations.
The process of conventional fat transplantation is as follows. The region of patient's body was small incised. A pipe (cannulae) having a hole on its distal end was inserted. Fat was aspirated through the cannulae using negative pressure. Liquid ingredients such as a serum, blood, injections in the extracted fat were removed except fat. The fat was bottled in a syringe and injected by manually through a thin needle.
When extracting a fat for transplantation, method of making negative pressure is classified into either use of machine or syringe.
In case of using machine for making negative pressure, the cannulae was equipped with a filter in its middle portion to strain fat. The fat was transferred and bottled into a syringe then injected.
Problems on this occasion are
1) Unless a large filter is used, fine hole of the filter gets to be clogged easily. Therefore generally suitable size of filters would be used as allowing for some fat loss, accordingly fat and other fine tissues were lost.
2) In the process of fat transfer from filter to syringe, the process became complicated and much time was required. Consequently the frequency of air contact becomes increased, so that the possibility of contamination gets high.
3) Also loss of a plenty amount of fat is caused because much amount of tissue stuck to the filter.
4) It takes much time and it is inconvenient since hand-operated pressure is used during injection.
Meanwhile, in case of using a syringe and hand-operated negative pressure, the syringe equipped with cannulae was injected into the human body at the maximum forward position of its piston. As the piston was pulled backward by manually, negative pressure was formed in space in front of the syringe piston. At this condition, user locked the piston.
Fat was aspirated while the syringe was reciprocated. Once the syringe was filled with the fat to some degree, the fat would be transferred to other places or a syringe for centrifuge/injection.
Extracted fat was transferred to a syringe for injection then transplanted. In order to use hand-operated injection, the piston syringe having a thick diameter can't be utilized such as a syringe for aspiration due to its big resistance when the fat passes through the needle.
Problems at this situation are
1) Negative pressure drops suddenly due to small amount of air flowing in the syringe at the very moment or just vapor pressure when piston is pulled and locked to form negative pressure. Therefore there is an inconvenience of releasing the lock and repeating again the process.
Efficiency of maintaining a negative pressure by only space of 50-60 cc is extremely low in comparison with the negative pressure formed by machine through air movement of thousands cc per 1 second.
Also the process is hard and troublesome to lock the piston of syringe as pulling it.
2) User has to transfer the aspirated fat to the syringe for centrifuge/injection, so that this process is also complicated and it requires a lot of time. At this time the fat gets to come into contact with a great quantity of air in several spaces, therefore the possibility of contamination is increased.
3) It takes much time and it is inconvenient since hand-operated pressure is used at the time of injection.
The said methods stand on the basis of hand-operated or mechanical method from the viewpoint of fat extraction, on the other hand transplantation of aspirated fat has been dependent upon entirely hand-operated injection method, accordingly some problems are indicated as following.
1) A problem is generated due to low injection pressure.
Pressure for fat movement through syringe needle is very large.
On this account, even though syringe for only fat injection utilizing the leverage is used, user must repeat the process to transplant 100 cc of fat dozens of times.
Therefore it takes much time, user suffers inconvenience. Besides jet pressure is also low. If the resistance at recipient site is strong, injection can't be performed, fat gets together in the place of weak resistance after all.
Thereby it causes following. First, desired cosmetic effect can't be displayed. Second, in case of fat gathered in one place and not spread out evenly, the contacting area with recipient site becomes small in comparison with same amount of fat. Lastly, survival rate is rapidly decreased in view of transplantation characteristic because the transplant gets to be alive with nutrition by contact before blood vessel has been formed with the passage of time.
Under the low survival rate, such as volume decrease, necrosis of middle site away from the contacting site, infection of necrosis tissues are discussed. Since they can be diverted into fatal infection symptoms all over the body, mass transplantation beyond regular amount (about 100 cc or more) is difficult and actually it has been hardly carried.
2) Another serious problem is infection. As the necrosis tissues become a good culture media, infection can spread in a flash. Although the fat tissue is not a necrosis, once it is separated from the body, its resistibility against germs gets extremely weak. Therefore it is unendurable against some germs, it can be spread into infection.
Infection appears when generally the number in the regular amount of tissue is more than a certain level. Even a germ exists in the air, the more the contacting time with non-sterilized indoor air and contacting areas, the higher the possibility of infection.
Lately a method using a suction receptacle itself as an injection receptacle is attempted, it can reduce occasion of indoor air contact and possibility of contamination from other receptacle. However it isn't suitable in case of mass fat transplantation such as over 100 cc of lipoinjection to one site since it uses small syringes.
At present, fat transplantation is used for treating wrinkles and small depression, but mass fat transplantation enough to breast augmentation is scarcely used due to infection and low survival rate.
Although it is carried out, it is considered as impracticable since it takes a lot of time and force.
3) Hand-operated injection method can't regulate injection pressure.
Since excessive high injection pressure affects not only adipose survival rate but also fat embolism, it is necessary to regulate precisely. In the process of fat entrance, resistance is generated. If the resistance can't be perceived, injection circumstance is invisible, so that equal distribution can't be accomplished at each part.